The National Cancer Institute has estimated that in the United States alone, 1 in 3 people will be struck with cancer during their lifetime. Moreover, approximately 50% to 60% of people contracting cancer will eventually succumb to the disease. The widespread occurrence of this disease underscores the need for improved anticancer regimens for the treatment of malignancy.
Due to the wide variety of cancers presently observed, numerous anticancer agents have been developed to destroy cancer within the body. These compounds are administered to cancer patients with the objective of destroying or otherwise inhibiting the growth of malignant cells while leaving normal, healthy cells undisturbed. Anticancer agents have been classified based upon their mechanism of action.
One type of chemotherapeutic is referred to as a metal coordination complex. It is believed this type of chemotherapeutic forms predominantly inter-strand DNA cross links in the nuclei of cells, thereby preventing cellular replication. As a result, tumor growth is initially repressed, and then reversed. Another type of chemotherapeutic is referred to as an alkylating agent. These compounds function by inserting foreign compositions or molecules into the DNA of dividing cancer cells. As a result of these foreign moieties, the normal functions of cancer cells are disrupted and proliferation is prevented. Another type of chemotherapeutic is an antineoplastic agent. This type of agent prevents, kills, or blocks the growth and spread of cancer cells. Still other types of anticancer agents include nonsteroidal aromastase inhibitors, bifunctional alkylating agents, etc.
Chemoimmunotherapy, the combination of chemotherapeutic and immunotherapeutic agents, is a novel approach for the treatment of cancer which combines the effects of agents that directly attack tumor cells producing tumor cell necrosis or apoptosis, and agents that modulate host immune responses to the tumor. Chemotherapeutic agents could enhance the effect of immunotherapy by generating tumor antigens to be presented by antigen-presenting cells creating a “polyvalent” tumor cell vaccine, and by distorting the tumor architecture, thus facilitating the penetration of the immunotherapeutic agents as well as the expanded immune population.
Ipilimumab is a human anti-human CTLA-4 antibody which blocks the binding of CTLA-4 to CD80 and CD86 expressed on antigen presenting cells and thereby, blocking the negative downregulation of the immune responses elicited by the interaction of these molecules. Since ipilimumab does not recognize mouse CTLA-4, an anti-mouse CTLA-4 antibody (clone UC10-4F10) was used in the studies presented herein to investigate the effect of CTLA-4 blockade with chemotherapeutic agents.
Microtubule-stabilizing agents, such as ixabepilone (IXEMPRA™) and paclitaxel (TAXOL®), are commonly used for the treatment of many types of cancer and represent an attractive class of agents to combine with CTLA-4 blockade.
In the studies described herein the combination of microtubule-stabilizing agents and CTLA-4 blockade was investigated in several murine tumor models with different sensitivity to each agent.
The present inventors have discovered for the first time the synergistic benefit of combining a microtubule-modulating agent with an anti-CTLA-4 inhibitor for the treatment of proliferative diseases. It is an object of the invention to provide efficacious combination chemotherapeutic treatment regimens wherein one or more microtubule-modulating agents are combined with one or more anti-CTLA4 agents for the treatment of proliferative diseases.